There are many natural sources of water in the world (rivers, ponds, lakes, seas, springs, surface and underground water tables, rain, . . . ), but the water coming from these natural sources is generally non-drinkable; moreover, growing environmental pollution makes the water of these natural sources increasingly less drinkable.
The majority of countries in the world have artificial water sources, i.e. public and private water distribution networks, but the water coming from these artificial sources is not always drinkable or truly drinkable (this is often the situation in some regions of countries such as Brazil, Russia, India, China, . . . ).
Non-drinkable water can contain, for example, large (gravel) and small (sand) solid particles, heavy metals, hydrocarbons, fertilizers, detergents, acids, ammonia, hydrazine, bacteria, microbes, viruses, . . . ; depending on the circumstances, one or more of these elements can be present. To make non-drinkable water drinkable the undesirable elements present must be removed.
Although there are various types of water purifiers on the market, none of these are completely satisfactory.
The Applicant has carefully studied water purifiers and has reached the following conclusions.
A first desirable feature for a water purifier is that it is capable of removing all possible undesirable elements or at least a high percentage thereof; in fact, it is not easy to predict which undesirable elements will be present in the water coming from a water source; moreover, the undesirable elements may vary in time.
A second desirable feature for a water purifier is that it is capable of completely or almost completely removing the undesirable elements, i.e. that the residual quantity thereof is extremely low.
A third desirable feature for a water purifier is that it is capable of removing the undesirable elements using only a small amount of energy or, in other words, that uses energy (in general this is electric energy) in a very efficient way; in fact, energy is required to remove the undesirable elements.
A fourth desirable feature for a water purifier is that it has a low running cost, and in particular that it requires few and inexpensive consumable materials; it would be ideal for there to be no consumable materials.
A fifth desirable feature for a water purifier is that it is easy to maintain, in particular to wash.
A sixth desirable feature for a water purifier is that it is of simple structure and construction and therefore of limited cost.
A seventh desirable feature for a water purifier, in certain situations, is that it is capable of operating without being connected to a powerful source of electric energy and, more specifically, that it is able to operate only or almost only using solar energy; in fact, in many situations in which there is no drinkable water there is also no public or private electric energy distribution network.